a sore point

a sore point/spot

a subject which someone would prefer not to talk about because it makes them angry or embarrassed (often + with ) I tried not to make any reference to Mike's drinking habits - I know it's a sore point with Kay at the moment.
See also: point, sore
References in classic literature ?
It is a sore point with me, this being told what I am to do or not do by you self-constituted lords of creation.
Philip saw that the rivalry was a sore point with the old man.
Tulliver manifested an unusual discretion, because she had recently had evidence that the going to school to a clergyman was a sore point with Tom, who looked at it as very much on a par with going to school to a constable.
The affair of the chaplaincy remained a sore point in his memory as a case in which this petty medium of Middlemarch had been too strong for him.